Vane for an architectural covering

ABSTRACT

A vane for an architectural covering, such as of the type used in a window opening, is designed for vertical suspension so as to resist twisting along its length. The vane is constructed in a tubular configuration and may have one or more internal hollow cells. The external configuration of the vane may simulate an air foil or have other related configurations. The vanes are preferably made of a material having diagonal, dimensional stability or memory, i.e. the ability to resist stretching in a direction diagonal to the length or width of the material.

This a continuation of application Ser. No. 08/437,959 filed May 10,1995 now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to coverings for architectural openingsand more particularly to an improved vane that may be used in a verticalwindow blind, door blind, or to otherwise furnish the interior of adwelling.

2. Description of the Known Art

Vertical blinds have been known in the art for some time. A typicalvertical blind has a headrail that contains a carrier mechanism, a tiltrod, and a plurality of operatively interconnected vertical vanes. Thecarrier mechanism includes a plurality of hangers for individuallysuspending the vertical vanes. The carrier mechanism is coupled to thetilt rod so that when the tilt rod is rotated the hangers are caused torotate about vertical axes which in turn rotate the vertical vanes towhich they are attached about the same axes. The vanes are always hungfrom their top edge with the hangers being undesirably visible orrequiring a valence to cover them up.

Vanes for vertical window blinds are typically made with one or more offour different types of materials. These materials are fabric,polyvinylchloride (PVC), aluminum and wood. The most common vanes aremade from either fabric, PVC or a combination of fabric and PVC. Fabricvanes offer a very appealing softer appearance. The fabric adds qualityto a vane and gives it a finished look. It also provides a designer witha number of design choices regarding the type of fabric to use for aparticular room. PVC vanes are plastic and therefor have a harderplastic appearance. One advantage of the PVC vane, however, is itsstrength. PVC vanes can be laminated or wrapped with fabric to providethe PVC strength with the fabric appearance.

There are disadvantages, however, to vanes made of fabric, PVC orcombinations thereof. Vanes made solely of fabric are thin, and tend totwist along their length when rotated from the top edge. They furtherare substantially two dimensional. PVC vanes also tend to twist alongtheir length when rotated from the top edge. The PVC vanes are alsonormally thin, even though they can be molded to provide a threedimensional shape. This shape is usually curved in cross-section, e.g. aC-shape or an S-shape, and the thickness of the vane is usually about1/8 inch or less. Additional thickness is too costly for the windowblind market.

Several hybrids exist for fabric vertical vanes. Fabric vanes are oftentreated with a stiffener to impart structural rigidity. The stiffenertakes away the fabric's hand or softness, but retains the look of thefabric. The vane will still twist, but less than non-treated fabricvanes. The treated fabric vanes also tend to curl in direct sunlight ifthe stiffener is not applied uniformly. Another hybrid, as mentionedpreviously, is a PVC vane laminated with a fabric. Such a vane has thestructural strength and three-dimensionality offered by a PVC vane withthe appearance of a fabric vane. The fabric in this case also looses itshand or softness. Problems common with PVC/fabric laminate vanes arethat in sunlight, the fabric may curl and delaminate, there is increasedassembly costs, the vanes are relatively heavy and when the fabric isonly laminated onto one face of the PVC, the reverse side isaesthetically displeasing. Another design includes a PVC vane core thatis wrapped loosely with fabric. This provides a softer product with afabric look, but it is very costly and difficult to fabricate. One otherapproach is a PVC vane with a groove along each edge so that a fabricinsert can be positioned in and along the faces of the PVC vane. Thisapproach is also costly, does not prevent longitudinal twisting and thereverse face and the grooved edges detract from the fabric appearance.

All of the prior art vertical vanes cast a distinct, well defined shadowon the adjacent vane when the vanes are completely closed and slightlyoverlapped in a window and are in direct sunlight. This shadow createsthe effect of stripes on the surface of the closed vertical blindresulting in objectionable aesthetics.

Vanes, more commonly referred to as slats, found in Venetian blinds. asopposed to vertical blinds, typically have different qualities as theyare disposed horizontally rather than vertically. In fact, some slatsfound in venetian blinds are of hollow construction. By way of example,U.S. Pat. No. 2,169,873 to W.D. Clark. Jr.; U.S. Pat. No. 2,326.454 toScipio S. Gentile; and U.K. Pat. No. 623.832 assigned to Chr. FabersFabriker disclose hollow slats for use in a venetian blind. Since slatsin venetian blinds are disposed horizontally, they must beself-supporting along their length. A self-supporting slat by its verynature must be somewhat rigid and therefore will not have a soft hand orfeel. The venetian blind slat is rotated about a horizontal longitudinalaxis by conventional tape ladders on which it is supported. This methodof support does not require energy transfer from one end of the slat tothe other as with vertical blinds. A vane in a vertical blind issupported from its top edge and is preferably rotated from its top edge.Therefore, it is not necessary that it be self supporting along itslength. To rotate a vertical blind vane, energy must be transmitted fromthe top of the vane to the bottom in order for the entire vane torotate. Uniform rotation along the entire length of the vane has been aproblem with prior art vertical vanes.

Therefore, it is an object of the present invention to provide a vanefor a vertical blind that is three-dimensional, has a soft hand or feel,that does not twist from top to bottom when rotated from the top butrather rotates uniformly, that hides the hanger of the carriermechanism, and that diffuses the light passing through the shade so thatno distinct, sharply defined shadows are formed.

SUMMARY OF THE INVENTION

The vertical vane of the present invention is preferably tubular inconfiguration thereby providing three-dimensionality and torsionalrigidity along its length. It is preferably formed from fabric havingdiagonal dimensional stability. Diagonal dimensional stability meansthat the vane fabric is not stretchy when pulled diagonally relative tothe machine direction of the fabric. The machine direction of the fabricis defined as the dimension of the fabric extending in the direction thefabric is moved through the machine in which it is manufactured. Thelongitudinal dimension of the vane preferably extends in the machinedirection of the fabric. The diagonal, dimensionally stable fabricallows the vane to carry torque along the length of the tubular vaneconstruction, thus inhibiting longitudinal twisting. Fabrics which arenot totally stable but at least have diagonal dimensional memory mayalso be used such that if slightly stretched along a diagonal will, overa short period of time, return to the original orientation.

The tubular vane may be made from tubularly manufactured fabrics, asingle sheet of fabric that is folded over onto itself to define ahollow vane or it may be made of multiple sheets of fabric joinedtogether to define a hollow vane. The fabric may also be creased along afold line to provide structural and/or aesthetic variety. A resilientlayer may be laminated to the inner side of the sheet, i.e., the sidethat will be inside the vane. The resilient layer helps to spring thevane fabric back from a flattened state that may occur during shipping.It also helps to retain the vane's three-dimensionality.

In multiple sheet configurations, two sheets or more may be joinedtogether with adhesive or by some other bonding method to create atubular structure. In this type of configuration, many different shapescan be attained and resulting bond lines replace the crease or creasesthat may be found in a vane constructed with a single sheet of fabric. Aprime feature in preventing twist in these arrangements and giving thevane torsional rigidity is diagonal dimensional stability or memory ofthe fabric. An advantage to this construction is that differentmaterials may be used to construct the tubular vane for aesthetics andother purposes.

Another aspect of the invention is its ability to hide the hardware thatis utilized to hang the vanes from a headrail. This makes for a far morepleasing aesthetic look. To achieve this, a hanger plate is insertedinto the open top end of each vane and attached to the top of the vane.The hanger plate is preferably positioned so that the hanger thatextends from a carrier mechanism mounted in the headrail issubstantially hidden within the hollow interior of the tubular vane.Ideally, the hanger plate is positioned so that the top of the vaneeither abuts the bottom of the headrail or almost abuts the bottom ofthe headrail when the vane is hung on the hanger.

The vane may have a single hollow portion or cell, or may have multiplehollow portions or cells. These portions or cells being defined by theway the product is folded and constructed. The typical and most costeffective vane will have a single hollow section, even though multiplecell constructions also have benefits.

Another advantage of the invention is that the hollow vane diffuseslight in a unique fashion. The shadow created by the overlap of twovanes is diffused by the tubular shape of the vane so the shadow is notapparent. This results in a product having a much more subdued andpleasing look over the harsh shadows of prior art vertical vanes. Thethicker the tubular vane, the more apparent this effect becomes.

Other objects, features and advantages of the present invention willbecome more fully apparent from the following detailed description ofthe preferred embodiment, the appended claims and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a frontal isometric view of a vertical window blindincorporating the tubular vane of the present invention.

FIG. 2 is a fragmentary isometric of the upper end of the tubular vaneshown in FIG. 1 showing a hanger plate attached to the vane.

FIG. 3 is a fragmentary front elevation of a window blind incorporatingthe tubular vane of the present invention in the extended closedposition illustrating how the hanger plates are hidden in the vanes.

FIG. 4 is a diagrammatic horizontal section taken through the tubularvane of FIG. 2 illustrating the diffusion of light passing through thevane.

FIG. 5 is a fragmentary horizontal section taken through severaloverlapped vanes of the type shown in FIG. 2 in the extended closedposition of a window blind.

FIG. 6 is a schematic isometric illustrating a method of forming thevane shown in FIGS. I through 5.

FIG. 6A is a section taken along line 6A--6A of FIG. 6.

FIG. 6B is a section taken along line 6B--6B of FIG. 6.

FIG. 6C is a section taken along line 6C--6C of FIG. 6.

FIG. 6D is a section taken along line 6D--6D of FIG. 6.

FIG. 7 is a section taken through a first alternative embodiment of thevane.

FIG. 8 is an end view of a pre-creased web of material used tomanufacture the tubular vane of FIG. 7.

FIG. 9 is a transverse section of a folded web during construction ofthe vane of FIG. 7 better illustrating the crease shown in FIG. 8.

FIG. 10 is an enlarged fragmentary section illustrating the relativesize of the crease.

FIG. 11 is an end view of a second alternative embodiment of the vane.

FIG. 12 is an end view of a third alternative embodiment of the vane.

FIG. 13 is an end view of a fourth alternative embodiment of the vane.

FIG. 14 is an end view of a fifth alternative embodiment of the vane.

FIG. 15 is an end view of a sixth alternative embodiment of the vane.

FIG. 16 is an end view of a seventh alternative embodiment of the vane.

FIG. 17 is an end view of a eighth alternative embodiment of the vane.

FIG. 18 is an end view of an ninth alternative embodiment of the vane.

FIG. 19 is an end view of a tenth alternative embodiment of the vane.

FIG. 20 is an end view of an eleventh alternative embodiment of thevane.

FIG. 21 is an end view of a twelfth alternative embodiment of the vane.

FIG. 22 is an end view of a thirteenth alternative embodiment of thevane.

FIG. 23 is an end view of a fourteenth alternative embodiment of hevane.

FIG. 24 is an end view of a fifteenth alternative embodiment of thevane.

FIG. 25 is an end view of a sixteenth alternative embodiment of thevane.

FIG. 26 is a table comparing the torque index of vanes manufactured inaccordance with the present invention with single ply and double plyplanar vanes.

FIG. 27 is a graph corresponding to the tabular information of FIG. 26.

FIG. 28 is a table comparing tubular vanes made of fabrics with andwithout diagonal, dimensional stability.

FIG. 29 is a graph corresponding to the tabular information of FIG. 28.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 1, a covering 30 in the form of an architecturalcovering device incorporating the vanes 32 of the present invention isillustrated. For purposes of the present disclosure, the covering 30will normally be referred to as a vertical window blind, it beingrecognized that the covering could be used for other architecturalpurposes such as on doors or to otherwise furnish the interior ofdwellings. The window blind broadly includes a headrail 34 suspendablefrom a wall or ceiling adjacent to a window opening and an operatingsystem (not fully shown) connected to the headrail and adapted tosuspend a plurality of the vertically extending vanes 32.

The operating system, which is not fully shown as it does not form partof the present invention, would preferably include a plurality ofcarriers associated with each vane 32 with the carriers beingoperatively engaged with a horizontally disposed tilt rod in theheadrail such that rotation of the tilt rod causes the carriers to pivotabout a vertical axis. Such operating systems for vertical vane windowcoverings are well known in the art. A hanger plate 36 (FIG. 2) affixedinternally to the upper end of a tubular vane is adapted to bereleasably connected to an associate carrier. The hanger plate can beaffixed to either side of the vane. The hanger plate is preferablyultrasonically bonded to the vane but may be affixed in any othersuitable manner so as to move in unison with the associated vane.

The window blind 30 is operative for movement between extended andretracted positions, as well as open and closed positions. In theextended position shown in FIG. 1, the vanes are uniformly distributedacross the window opening, while in the retracted position (not shown),the vanes are horizontally stacked together adjacent either or bothsides of the window opening. The vanes are pivotal to move the blindbetween the open and closed positions. In the open position shown inFIG. 1, the vanes extend perpendicularly to the headrail, while in theclosed position of FIGS. 3 and 5, they preferably partially overlap inshingle-like touching relation and extend in substantially parallelrelation to the headrail.

Referencing FIG. 2, a vane 32 fabricated in accordance with the presentinvention can be seen to be made of a single strip or web of sheetmaterial, preferably fabric, formed into an elongated tube so as to givethe vane torsional rigidity along its length. The vane therefore has aninner surface 38 and an outer surface 40. The material may be a singlelayer or a laminate. If it is a laminate, the inner surface of thelaminate would normally be functional and possibly not as aestheticallypleasing while the outer surface of the laminate would normally be lessfunctional and more aesthetically pleasing. The tubular construction ofthe vane is both structurally sound and aesthetically pleasing.

The vane 32 has two equal length outwardly convex outer walls 42 and 44defining a smooth rounded curve along one folded side or front vanesection 46 of the vane and a relatively thin substantially flat tail 48at the other side or rear vane section 50 of the vane where the freeedges 52 of the strip of material from which the vane is made aredisposed proximate each other. The free edges 52 of the strip are joinedtogether, as with adhesive, along a bond line 54 extending the length ofthe vane. The folded one side 46 of the vane is rounded so as tosimulate a rounded pleat found in conventional draperies. The spacingbetween the walls 42 and 44 of the vane at the location where they aremaximally spaced, as designated by the letter "X" in FIG. 2, ispreferably in the range of 1/8" to 1" for a vane that is three andone-half inches wide from the rounded side 46 to the tail side 50. Thisparticular structure of the vane makes it possible to use a number ofmaterials, many of which do not have inherent structural rigidity, butwhich are inherently somewhat biased toward a flat orientation to createa hollow tubular vane suitable for use in a vertical vane windowcovering. The availability of various materials creates a wide varietyof choices of textures, colors and fabrics.

The aesthetic attributes of the design of the vane 32 stem from itthree-dimensionality, the hollowness of the vane, the tail 48, and thefact that different materials may be used in the construction. Thethree-dimensionality of the vane provides a softer, less harshappearance in the window than conventional fabric vertical vanes. Thesoft appearance is present in both the open and the closed positions ofthe vanes. Further, in the retracted position the blind provides acurtain like look.

The hollow vanes 32 provide two significant functional advantages overprior art vertical vanes. The first is that the hanger plate 36 can betotally hidden within the vane as best seen in FIGS. 2 and 3. In priorart vertical blinds the hardware is visible and is not very attractive.The second advantage of the hollow vane is that it diffuses light in afashion that breaks up the harsh shadows created with prior art verticalvanes. This diffusion is a result of two effects as illustrated in FIG.4. The first effect results in diffusion when direct sunlight isdiffused by the first wall 42 of the vane so a distinct shadow is notcast on the second wall 44 of the vane. The light diffusion is inherentto a fabric and is enhanced by the second wall of the tubular vane. Thesecond effect is the internal reflection of sunlight within the hollowinterior of the tubular vane. If the inner surface 38 is white, itreflects light. The reflected light is spread over the entire surface ofthe vane and thus, instead of a distinct shadow at the point of overlapof two adjacent vanes, a diffuse or subtle shadow occurs.

The relatively flat and thin tail 48 of the vane 32 is adapted tooverlap (FIG. 5) an adjacent vane when the window covering is in theextended closed position and, therefore, improves vane closure of theblind. Enhanced vane closure improves the overall performance of theblind for providing privacy and light control. It also results in a moreattractive product because no unwanted light can shine through gaps inthe blind. It will be appreciated that whether or not the blind is inthe open or closed position, a rounded surface of the vane faces theinterior of the building structure in which the blind is mounted therebypresenting a soft appearance similar to conventional drapery.

The vane 32 is made of a flexible material and functions best if thematerial has diagonal, dimensional stability. Diagonal. dimensionalstability is a characteristic of a fabric that substantially preventsthe fabric from stretching or shrinking along a line diagonal to eitherthe machine direction of the fabric or the cross-direction of thefabric. For purposes of the present disclosure, a fabric that isdiagonally dimensionally stable is defined as a fabric that can bestretched no more than 10% along a forty-five degree diagonal to themachine direction of the fabric when a force of eight ounces is appliedbetween two points along this diagonal. As mentioned previously, it ispreferable that the longitudinal dimension of the vane extends in themachine direction of the fabric. The diagonal, dimensional stability isa factor in the vanes'ability to resist twisting from top to bottom whenrotated from the top. The diagonally, dimensionally stablecharacteristic of the material facilitates the transfer of torque alongthe length of the tubular vane. The diagonal, dimensional stability ofthe fabric, in conjunction with the hollow structure of the vane,essentially prevents longitudinal twisting even though the vane willreadily bend under gravity if disposed horizontally.

Examples of materials having diagonal, dimensional stability are almostall nonwoven fabrics, and some knit fabrics. Wovens are generally quitestretchy when pulled diagonally, though it is not beyond comprehensionthat a diagonally, dimensionally stable woven could be created such asby laminating the woven to a stabilizing nonwoven of some kind, a film,or by using large amounts of stiffener.

It is preferred, though not essential, that the material give a nicequality of transmitted light. The preferred material is white so as toprovide a transmitted light that is of a nice white color and quality.Major variations do exist in the quality of vane materials and it isdifficult to judge the quality of the light other than to testvariations with a consumer panel.

The strength requirement for material is that it be strong enough to notbe torn easily and that it does not pill when abraded. The requirementthat the material does not tear is especially relevant at the locationin the vane where the hanger plate 36 is attached.

The material desirably also has a very nice hand. The hand of a fabricis its tactile qualities that include softness, firmness, elasticity,fineness, drape and other qualities perceived by touch. A fabric with anice hand can be used for the vane as long as it has or can be providedwith diagonal, dimensional stability since the fabric does not have tobe treated with a stiffener to transfer torque when in a tubularconfiguration.

A material that has performed satisfactorily for constructing the vaneis a 100 gram/m² acrylic bonded polyester spunbond nonwoven fabricmanufactured by Unitika Corporation headquartered in Japan. Anothersuitable material is an opaque knit fabric identified by style number34184 and manufactured by Guilford Mills of North Carolina. Both ofthese fabrics give a good balance of the characteristics describedabove. In addition, knitted or woven fabrics could be laminated to anonwoven or knit fabric of the type mentioned.

While it is preferred that the fabric be diagonally, dimensionallystable, fabrics which have diagonal, dimensional memory may also beused. A fabric with such memory might be slightly more stretchable alongits diagonal, then a fabric that is diagonally, dimensionally stable butwill return to its original orientation over a relatively short periodof time. For purposes of the present disclosure, a tubular vane made inaccordance with the present invention and from a fabric that hasdiagonal, dimensional memory will return to its original orientation inless than two minutes when twisted along its longitudinal axis 45degrees from top to bottom and the vane is 84 inches in length and 3.5inches in width. In other words the fabric would have some degree ofresiliency along its diagonals.

As mentioned previously, the vane 32 is made from an elongated web orstrip of material. The strip is rectangular in configuration so as tohave the aforenoted two longitudinally extending side edges. The stripis formed into a tube generally simulating an airfoil. This tubularconstruction provides the vane 32 with torsional rigidity along itslength which is enhanced by the use of a diagonally, dimensionallystable fabric. The torsional rigidity resists the twisting that priorart vertical vanes have exhibited.

The preferred method of producing the vane 32 requires several stepsschematically illustrated in FIGS. 6, 6A, 6B, 6C and 6D. The first stepis heat stabilization of the material used to manufacture the vane ifthe material is a fabric. Non-fabrics, such as paper or the like, wouldnot have to be heat stabilized since such materials would not be subjectto shrinkage. Heat stabilization is done to prevent differentialshrinkage of the vane which will cause the vane to bow. The heatstabilization is performed while a web or strip of the fabric 55 is runthrough a fabric straightener 57. A seven-inch wide web has been foundsuitable but other widths of material could be used. The fabricstraightener may consist of a heat roller 59 and a cooling roller 61.The fabric straightener takes any inherent bow, or curve, out of the rawfabric before it is further processed. The fabric straightener 57 isdesirable because the tubular vane construction can amplify any curvepresent in the raw fabric into a significant bow in the finished vane.For example, if a roll of 7-inch wide vane material is rolled and laidflat on the floor over a length of 50 feet, the material may bow as muchas 1/4 inch over the 50-foot length. When this bowed material isproduced into a vane, the vane might also have 1/4 inch or more of bowin a six foot length. This amount of bow is typically unacceptable inthe window covering industry where aesthetics are of prime importance.In fact, any bow greater than about 1/8 inch in a vane that is 84 incheslong or less is generally unacceptable.

The straightened fabric 55 is then folded by a folder or former 63 asillustrated in FIGS. 6, 6A, 6B, 6C and 6D by simultaneously raising theside edges 65 of the web until they are disposed proximate each other asthe web is advanced through the folder or former. The sides should beraised simultaneously rather than folding one side onto the other side,because the stresses caused by folding will be uniform on both sides ofthe web. The folding is accomplished by running the web through thefolder or former that has an internal contoured wall that captures theweb and gently causes both sides of the web to move toward one another.The sides edges 65 eventually lie proximate to each other. The foldingapparatus preferably has a central member or beam 67 that holds thecreased web down as it is folding the sides of the web.

FIGS. 6A-6D illustrate in cross-section the configuration of theinternal wall 75 of the folder or former 63 and its affect on the web offabric 55 as the fabric is moved through the folder. It should beappreciated that the fabric inherently wants to remain flat or in otherwords is somewhat biased toward a flat orientation so that it willnaturally follow the contours of the internal wall of the former. As canbe seen in FIG. 6A, the folder at a location upstream from itslongitudinal center defines a relatively wide trough wherein the sideedges 65 of the web are lifted slightly. In FIG. 6B, which is across-section downstream from FIG. 6A, the trough is slightly narrowerand the side edges 65 have been raised considerably. The lowermostportion of the web, at the longitudinal center of the web, has beenfolded into the rounded side 46.

FIG. 6C is a cross-section near the downstream end of the folder and itwill be seen that the trough is shaped generally like a narrow U and iseven narrower than it is at the extreme downstream end shown in FIG. 6D.Further, the lower end of the trough has a relatively narrow V-shapedsection 77 that forms a very slight crease in the rounded and foldedside 46. The crease is not enough to form a permanent bend in the fibersof the fabric but only enough to deform the fabric so that the fold isslightly narrower than it would be without the slight crease and isspringy or resilient so as to retain the bias that urges the side walls42 and 44 away from each other. The bias on the side walls forces thetubular fabric web to expand and follow the contour of the inner wall 75of the folder as it widens at the downstream end of the folder as shownin FIG. 6D.

When the fabric is completely folded, two continuous belts 69 (FIG. 6)traveling at the same speed adjacent to one another can be used to nipthe fabric and pull the fabric through a glue applicator 71. The glueapplicator would insert glue along the bond line 54 (FIG. 2) between thetwo walls 42 and 44 along the side edges 65. Side pressure from the twobelts 69 can then be used to close the walls onto the line of glue tocreate a permanent bond. The preferred glue for this application is aGriltex 6G manufactured by EMS Inc. of Sumter, S.C. Misalignments informing the vane as described may cause twisted or bowed vanes, somaintaining proper alignment of the web of fabric as it is folded andglued is important. It should be appreciated that the glue used informing the vane has no roll in the functional characteristics of thevane but rather serves only to secure the vane material to itself. Thiscould be achieved in other manners such as by sewing, stapling orclamping.

The folded and glued web in its tubular configuration can then betransferred to a cutting mechanism 73 (FIG. 6) to cut the web intodesired lengths. One such mechanism is a conventional guillotine cutoffwhich may be a single-rotation-type guillotine that is spaced from thetubular web so that the folded and glued web can run through it freelyand only impinges upon the vane when actual cutting occurs. The singlerotation type cutter can produce any length vane 32. After the vane iscut to length, it would be accelerated away from the guillotine cutterto where the hanger plate 36 is incorporated into the vane as byultrasonics and subsequently forwarded for packaging or incorporationinto the finished window blind product.

Another advantage to a vane 32 formed as shown in FIG. 2 is that thevane can be packaged in an almost completely collapsed state and thefabric at the rounded fold will cause the vane to rebound or open upwhen placed on a blind. The amount of rebound is dependent on the typeof fabric used. A resilient fabric will open up fuller than anon-resilient fabric.

A first alternative embodiment of the vane of the present invention isillustrated in FIG. 7. The vane 58 of FIG. 7 in transverse cross-sectioncan be seen to have a flat short wall 60 and an outwardly convex longwall 62. The structure also has a well defined permanent longitudinalcrease 64 along a folded side 66, and a tail 68 along the other sidewhere the short wall and the long wall are adhesively joined along abond line 70 extending the full length of the vane. The advantage tothis particular structure is that due to the fact that the vane materialis somewhat biased toward a flat orientation, the long wall 62 exerts alateral biasing force on the short wall 60 at the crease 64 and alongthe bond line 70 so that the short wall is always biased outwardly andthus remains flat. Additionally, the short wall prevents the long wallfrom extending outwardly beyond the width of the short wall thuspreventing the long wall from collapsing on itself. These offsettingforces between the short and long walls help the structure retain itsshape when hung in a vertical orientation. The convex long wall 62 isalso seen to be rounded so as to simulate a rounded pleat found inconventional draperies. The spacing between the walls 60 and 62 of thevane at the location where they are maximally spaced, as with the firstdescribed embodiment, is designated by the letter "X" in FIG. 7 and ispreferably in the range of 1/8" to 1" for a vane that is 31/2" wide.

The embodiment of FIG. 7 is also preferably formed from an elongated webor strip of fabric. The permanent longitudinal crease 64 (FIGS. 8. 9 and10) is established in any conventional manner in a central region of theweb. The location of the crease is in the region where the tubular vaneis folded, as shown in FIGS. 8. 9 and 10. There is no later heat settingof the crease, so it must be made permanent. In making the creasepermanent, the fibers of the fabric web must be flattened without beingcut. In the preferred embodiment of the vane, the flattening of thefibers occurs over a width of at least two times the thickness of thefabric web as best seen in FIGS. 9 and 10. A preferred thickness of thefabric would be 10 1/2 mils. To achieve such a crease, a blunt creaseris used that has a contact area of at least two times the fabricthickness and compresses the fabric to about one half its normalthickness. This crease width is preferred, but the vane will function ifthe crease is narrower or wider.

The desire for a permanent crease as described is better understood byreferring to FIGS. 9 and 10. FIG. 10 shows a fabric web at the point ofthe crease 64 while FIG. 9 shows what the crease looks like when the webis folded. It is clear from this illustration that instead of gaining asharp fold line that may tear when folded, the crease provides for agentle fold that does not have a sharp fold line. This relatively broad,blunt crease helps the material of the vane retain its airfoilconfiguration by providing more of a divergent bias on the sides orsections of the web defined by the crease than would exist with anarrower crease.

A second alternative embodiment of the vane of the present invention isillustrated in FIG. 11. The vane 74 of FIG. 11 can be seen to be verysimilar to the first described embodiment of FIG. 2 except that alongitudinal crease 76 is formed in the fold along the associated side78 of the vane. The crease 76 is preferably a blunt crease as of thetype described in connection with the first alternative embodiment ofFIG. 7 and extends substantially along the front vane section at thelongitudinal center line of a web of fabric from which the vane is made.The side 80 of the vane opposite the creased side 78 again forms arelatively thin and flat tail or rear vane section 82 where the two sideedges 84 of the web are bonded together.

To obtain more rebound, a vane 86 (FIG. 12) of the configuration shownin FIG. 2 can be modified by adding a strip 88 of resilient materiallongitudinally along a fold 90 on the inside of the vane 86 asillustrated in a third alternative embodiment in FIG. 12. The resilientstrip 88 can be narrow or wide. An example of a resilient strip that issuitable for use in the vane is a 50 gram/m² 6 denier latex bondedpolyester typical of that used as quilt battens and found in most fabricstores. Strips of the resilient material can alternatively be bonded tothe fabric transverse to the longitudinal axis of the vane. Thesestrips, if a resilient polymer is used, will provide cross-directionalstrength to the vane and work to force the vane open.

The fabrics used for the first, second and third alternative embodimentsof the preferred invention illustrated in FIGS. 7, 11 and 12,respectively, are the same as those described for the embodiment of FIG.2. Again, the most important attribute of the fabric is that it havediagonal, dimensional stability or memory. Another important attributeof the fabric is that it have a good hand. One particular fabric thatworks very well with these three embodiments is a laminate of a wovenand nonwoven polyester. The methods of manufacturing the vanes aresubstantially the same as that for manufacturing the vane 32 of thefirst described embodiment.

FIGS. 13 through 15 show fourth, fifth and sixth alternate embodiments,respectively, of the vane shown in FIG. 11 but folded and creaseddifferently. All three embodiments would again preferably be made of thesame fabric as the previously described embodiments. The vane 98 shownin FIG. 13 does not have a tail, the walls 100 and 102 are symmetricwith a crease 104 along a central region of the web from which the vaneis formed and a bond line 106 extending the full length of the vane islocated between the side edge of one wall 100 and an internally foldedflap 108 at the side edge of the other wall 102. The generalcross-sectional shape of the vane 98 is obloid. One advantage of thisdesign is that the bonding area is hidden.

FIG. 14 represents a vane 110 that has a tail 112 defined by bonded flatlegs 114 along the side edges of each wall 116 and 118 respectively. Abond line 120 extends the full length of the vane. The walls 116 and 118are of equivalent width as are the flat legs 114. The walls are equallybowed and terminate substantially along the longitudinal center line ofthe web in three longitudinally extending creases 122, 124 and 126 whichdefine a longitudinally extending indentation 128. The creases bias thevane toward an open condition should it be collapsed.

FIG. 15 represents a vane 130 that has a convex short wall 132 and aconvex long wall 134. The short wall 132 is bonded or otherwise affixedto the long wall 130 with a line of adhesive 136 extending the fulllength of the vane at an intermediate location along the width of thelong wall so as to define a single layer tail 138 along the free edge ofthe long wall. The opposite side edge of the vane is folded with orwithout a crease to define a flap on the short wall that identifies thelocation on the short wall where it is bonded to the long wall. Thisembodiment improves vane closure as the tail 138 establishes a greateroverlap between vanes when the vanes are in the closed position.

FIGS. 16 through 19 show seventh, eighth, ninth and tenth alternateembodiments, respectively, of the vane of the present invention. Theseembodiments are made from multiple webs of material instead of a singleweb. The embodiments all utilize a fabric with diagonal dimensionalstability or memory, they all are of tubular structure, and they have asimilar if not identical appearance to earlier described embodiments.The advantage to a multiple web type of structure is that it may bepossible to use two webs of different colors, textures, or evendifferent materials to create a vane. With webs of different materials,there may be differential shrinkage between the two types of materialsresulting in vane bowing. Thus preshrinkage of the raw web materialsprior to manufacture of the vane is desirable.

The seventh embodiment shown in FIG. 16 is a multiweb vane 150 that hasa shape similar to the shape of the vane shown in FIG. 7. This vane ismade of two individual webs of materials joined together by lines ofadhesive 152 extending the full length of the vane to form asubstantially flat short wall 154 and a convex long wall 156 of thetubular vane. The long wall 156 is longitudinally creased inwardly at afold 158 adjacent one longitudinal edge to define a flap 160. The flap160 is tucked inwardly and bonded with the adhesive 152 to the shortwall 154. The opposite edges of walls 154 and 156 are also bondedtogether with the adhesive 152 to form a tail 162.

The eighth alternative embodiment shown in FIG. 17 represents asymmetrical multiweb vane 164 having internal flaps 166 defined bycreases 168 adjacent opposite edges of the equal length convex walls 170and 172 of the web. The flaps 166 are joined together with adhesive 174extending the full length of the vane.

FIG. 18 represents a multiweb vane 176 in which a substantially flatshort wall 178 is contained within a convex long wall 180 havinginwardly directed flaps 182 along opposite side edges formed bycreasing. The flaps 182 have an inner surface facing the short wall andthe short wall is bonded to the inner surface of the flaps 182 of thelong wall with adhesive 184 extending the full length of the vane.

The tenth alternative embodiment illustrated in FIG. 19 shows a multiwebvane 186 that is a variant of the vane 176 shown in FIG. 18. Thedifference in the vane 186 and the vane 176 disclosed in FIG. 18 is anadditional set of glue lines 188 extending the full length of the vanebonding the long wall 190 to the short wall 192 along a portion of thelong wall adjacent to flaps 182 so that the short wall is bonded to thelong wall on both faces of the short wall.

FIGS. 20 through 23 represent multicellular embodiments of the vane ofthe present invention. These vanes may include two or more cells, but itis still desirable that the fabric have diagonal dimensional stabilityor memory to optimize proper functioning. A cell divider may be made ofthe same or different materials. A cell divider may be used both tocreate multiple cells or to provide blackout or darkening features tothe vane product. The vanes may be made using multiple webs or madeusing a single web and folding the web differently. The cell dividerwhen inserted between the vane edges helps to prevent collapsing of thevane, but it does not have to be inserted between the edges. By makingthe cell divider from a material different than the body of the vane, itcan be used to increase the bending stiffness of the vane by using astiffer material or to enhance other physical properties such asinternal light or heat reflection.

FIGS. 20 through 22 represent multicellular vanes that are foldeddifferently but made from a single web. In FIG. 20, a vane 202constituting an eleventh alternative embodiment of the present inventioncan be seen to be formed from a single strip of material having equallength convex wall portions 204 and 206 and a flat cell divider portion208. The wall portion 204 and 206 define an external structureconfigured substantially the same as that of FIG. 11. The cell dividerportion 208 is flat and has a flap 210 at one edge, which is also oneside edge of the web from which the vane is made, bonded with adhesive212 to the internal closed end of the vane along the full length of thevane. The opposite edge of the cell divider portion which is actually afold line 214 is bonded with adhesive 216 along a bond line extendingthe full length of the vane that secures the opposite edge of the celldivider portion to the two walls of the vane. The wall 204 is definedbetween the other side edge of the web from which the vane is made and afirst creased fold line 218 while the second wall 206 is defined betweenthe first fold line 218 and the second fold line 214. The cell divideris then of course formed between the second fold line 214 and the flap210.

The twelfth alternative embodiment shown in FIG. 21 is also amulti-cellular vane 220 fabricated from a single web. The web is creasedalong two longitudinal fold lines 222 and 224 which are equally spacedfrom opposite edges 226 and 228 respectively of the web. The fold lines,however, are spaced apart from each other a greater distance than theyare from each adjacent edge of the web. The vane 220 is then formed byfolding the outermost sections 230 and 232 of the web (the sectionsbetween the fold lines and the outer edges of the web) in oppositedirections so as to overlap on opposite sides the intermediate portion234 of the web between the fold lines. The opposite edges 226 and 228 ofthe web are then bonded with adhesive 236 to the intermediate portion234 along the full length of the vane adjacent to the longitudinal foldlines so as to form the vane as illustrated with a generally S-shapeddivider 238. It will be appreciated that the divider 238 is longer thaneither wall defined by the outermost sections 230 and 232 and thereforebiases the walls outwardly into the desired configuration.

FIG. 22 is an illustration of the thirteenth alternative embodiment ofthe invention and can be seen to have an external configuration similarto the embodiment of FIG. 17. The vane 240 is a multi-cellular vane,however, and is fabricated from one web that has four longitudinalcreases. Two outermost creases 242 are spaced slightly inwardly from thelongitudinal edges of the web so as to define short flaps 244. Two innerlongitudinal creases 246 are equally spaced from the outer creases 242,but the spacing between the inner creases is less than the spacingbetween associated inner and outer creases. The flaps 244 are foldedinwardly and bonded with adhesive 248 along the full length of the vaneto the section of the web between the innermost creases 246 so as toform a vane having convex walls of equal length and a flat intermediatecell divider 250.

FIG. 23 shows the fourteenth alternative embodiment of the vane of thepresent invention, and the vane 252 can be seen to be made from threewebs that are bonded together with adhesive 254. Two outermost webs areof equal width and define convex outer walls 256 of the vane. The outerwalls 256 have sandwiched therebetween a shorter web or cell divider 258that is of flat configuration with the shorter web being bonded to theouter walls with the adhesive 254 adjacent to the longitudinal edges ofthe web and the walls along the full length of the vane. One advantageof a multi-web construction as illustrated in FIG. 23 is that differentfabrics or films may be used in the construction of the vane. Forexample, the vane may have as its cell divider 258 a sheet of metalizedpolyester film that gives the product room-darkening capabilities.Because the walls 256 of the vane are of equal width, i.e. symmetric,the different material characteristics will not affect vane bowing.Thus, blackout materials, insulating materials or sound-deadeningmaterials may be added to the vane construction without an adverseaffect on vane performance.

A fifteenth alternative embodiment of the invention is illustrated inFIG. 24 and can be seen to be made from two webs bonded together withadhesive 262 along the full length of the vane. The webs are joined soas to define a convex long wall 264 and a flat short wall 266 withrelatively thin tails 268 defined at the side edges of the webs wherethey are bonded together. The convex curvature of the long wall 264advantageously tends to keep the short wall 266 taught and flat.

FIG. 25 illustrates a sixteenth embodiment of the invention. In thisembodiment, a single web or strip of material is folded and creased at272 substantially along a longitudinal centerline and the two halves ofthe web defined on either side of the crease 272 are formed intoS-shaped configured walls 274 and 276 which are interconnected as bybonding with adhesive along the contiguous side edges 278 and along amid line 280 between each side edge 278 and the crease 272. A curvedvane 282 that is also S-shaped in configuration is thereby formed withtwo crescent shaped cells 284.

It will be appreciated that the vane shape, number of cells and numberof webs or strips used to manufacture a vane can vary. The two mostimportant features of the vane, however, remain that it be tubular inconstruction, i.e., it be hollow in one or more of its cells, and thatthe vane preferably be made of a fabric or a material that has diagonaldimensional stability even though materials having diagonal dimensionalmemory would also work satisfactorily. The spacing between the outerwalls for any of the alternative embodiments is preferably in the rangeof 1/8" to 1" at their maximum displacement.

To illustrate the advantages gained by producing vanes in a tubularconfiguration as described hereinabove and from materials havingdiagonal. dimensional stability or memory, the results of testscomparing standard typical vanes found in the art with those of thepresent invention are presented in FIGS. 26 and 28.

For purposes of the tests from which the data was obtained, the vaneswere cut to be 84 inches in length and 3.5 inches wide. The vanes weresuspended from the top edge with centrally located clips approximately3/8 inch in width and measurements were made to determine the force thathad to be applied at the opposite lower free bottom edge of the vane totwist the opposite or bottom edge of the vane through varying degrees.This force is referred to herein as the torque index.

The first test compared a single-ply and double-ply planar prior arttype vane to a tubular vane made in accordance with FIG. 7 of thepresent invention wherein the vanes were all made from a 100 gram/m²acrylic bonded polyester spun bond nonwoven fabric manufactured byUnitika Corporation of Japan. The test results are shown in FIG. 26. Theamount of force required to twist the lower edge of the vanes throughthe designated number of degrees is recorded in the three tables of FIG.26. It will there be seen that the force required to rotate anon-tubular, single-ply fabric vane through 45 degrees, for example, isapproximately 1.5 grams. The force required to rotate a non-tubular,2-ply fabric vane through 45 degrees is slightly more than 1.5 grams. Incontrast, the force required to rotate a tubular vane constructed inaccordance with the present invention through 45 degrees is 59 grams,therefore illustrating the vastly improved resistance to torque obtainedby a tubular vane constructed in accordance with the present invention.A graph illustrating the comparative data set forth in FIG. 26 is shownin FIG. 27.

The advantages obtained from utilizing material having diagonal,dimensional stability relative to material that does not have suchstability is illustrated in data presented in FIG. 28. FIG. 28 has twotables, one directed to a tubular vane configured as shown in FIG. 7made of a woven fabric and specifically a woven slub polyester, whichfabric does not have diagonal, dimensional stability or memory and anidentically configured tubular vane made of a polyester knit fabric,that does have diagonal dimensional stability. Both fabrics were ofequal weight.

In looking at the tabular information in FIG. 28, it will be appreciatedthat the force required to rotate a woven fabric tubular vane withoutdiagonal. dimensional stability or memory through 45 degrees is justless than 2 grams of force. On the other hand, the force required torotate a tubular knit fabric vane having diagonal, dimensional stabilitythrough 45 degrees is 26 grams. Accordingly, a dramatic difference inforce necessary to rotate the vane through 45 degrees is illustratedshowing that materials having diagonal, dimensional stability are farpreferable for use in a vane. A graph illustrating the comparisonbetween the knit fabric having diagonal, dimensional stability and awoven fabric not having such stability is illustrated in FIG. 29.

It will be appreciated from the above information that the structuralconfiguration of the vane and the fabric from which it is made have asignificant bearing on the vanes torsional resistance to twisting. Whilethe torque index of the vane may have varying importance to amanufacturer or consumer, applicant has found vanes to be desirable thathave a torque index in excess of 10 grams for 45 degrees of rotationwhen the vanes are 84 inches in length and 3.5 inches wide.

While the present invention has been disclosed in connection with apreferred embodiment thereof and several alternate embodiments, itshould be understood that there may be many other embodiments which fallwithin the spirit and scope of the invention as defined by the followingclaims.

What is claimed is:
 1. A vane for an architectural covering used in an architectural opening wherein a plurality of such vanes are suspended, said vane comprising in combination:an elongated hollow tubular body having first and second walls at least one of which is outwardly convex, said body being formed from a flexible material such that body will inherently bend transversely of its length when the body is disposed horizontally, is unsupported along its length and is of a length suitable for use in said architectural opening.
 2. The vane of claim 1 wherein said tubular body is formed from an elongated strip of material having two longitudinally extending side edges and wherein the strip has a fold substantially along a longitudinal centerline such that the side edges lie proximate to each other and wherein said first and second walls are secured together proximate said side edges.
 3. The vane of claim 2 wherein said flexible material is diagonally, dimensionally stable.
 4. The vane of claim 2 or 3 wherein said fold is a crease.
 5. The vane of claim 2 or 3 wherein said side edges are imnediately adjacent to each other.
 6. The vane of claim 2 or 3 wherein said edges are displaced relative to each other so as to define a single layer tail along one side edge.
 7. The vane of claim 2 or 3 further including at least one strip of resilient reinforcing material bonded to said body in the hollow interior along said fold.
 8. The vane of claim 7 wherein said reinforcing material extends longitudinally of the vane.
 9. The vane of claim 7 wherein there are a plurality of said strips of reinforcing material which extend transversely of the vane.
 10. The vane of claim 2 or 3 wherein one of said side edges is folded longitudinally back upon the strip to define an elongated flap along the associated side edge, said flap being secured to the other side edge.
 11. The vane of claim 2 or 3 further including three longitudinally extending creases along said fold, so as to define a longitudinally extending indentation along said fold.
 12. The vane of claim 4 wherein said crease is formed in an inner surface of said tubular body by compressing the material over an area that is approximately twice the thickness of the fabric.
 13. The vane of claim 2 or 3 wherein said first wall of said tubular body is shorter than said second wall.
 14. The vane of claim 13 wherein said first wall is substantially flat.
 15. The vane of claim 2 or 3 wherein said first and second walls are of equal width.
 16. The vane of claim 15 wherein said first and second walls are outwardly convex.
 17. The vane of claim 1 wherein said tubular body is formed from two interconnected strips of material defining said first and second walls of said body, each wall of said body having longitudinally extending side edges being proximate to he associated side edges of the other wall.
 18. The vane of claim 17 wherein one side edge of one of said walls is folded back onto said one wall to define a longitudinally extending flap and wherein said flap is secured to the associated side edge of the other wall of said body.
 19. The vane of claim 17 wherein each side edge is folded back onto the associated wall of said body to form a longitudinally extending flap and wherein the flaps on one wall are secured to the flaps of the other wall.
 20. The vane of claim 17 wherein the side edges of one of said walls are folded back onto said one wall to form longitudinally extending flaps and wherein said flaps are secured to the associated side edges of the other wall.
 21. The vane of claim 20 wherein said other wall is flat and said one wall is longer than said other wall and said one wall is convex outwardly.
 22. The vane of claim 20 wherein said flaps have an inner surface facing the associated wall of said body and wherein said flap is secured to said side edges of the other wall along said inner surface.
 23. The vane of claim 20 wherein said side edges of said other wall are further secured to a portion of said one wall adjacent to the associated flap.
 24. The vane of claims 1 or 3 wherein said flexible material has elongated first and second side edges, a first fold spaced from said first side edge and a second fold equally spaced from said second side edge, and wherein said first side edge is secured to a portion of said strip proximate said second fold and said second side edge is secured to a portion of said strip proximate said first fold so as to define a longitudinally extending divider portion of said strip dividing the tubular body into two cells.
 25. The vane of claim 24 wherein the spacing between said fold lines is greater than the spacing between each fold line and the associated side edge of the strip so that said divider is generally S-shaped in cross-section.
 26. The vane of claim 24 wherein each side edge is folded back onto said strip to define longitudinally extending first and second flaps along said first and second side edges respectively and wherein said first flap is secured to said strip proximate said second fold and said second flap is secured to said strip proximate said first fold.
 27. The vane of claim 26 wherein said folds are spaced apart a shorter distance than their spacing from the associated side edge such that said divider is flat.
 28. The vane of claims 1 or 3 wherein said tubular body is formed from three interconnected strips of material, each strip having elongated first and second side edges, two of said strips are wider than the third of said strips and define said first and second walls of said body, and wherein the associated side edges of said strips are secured together such that said third strip defines a divider dividing said body into two cells.
 29. The vane of claim 28 wherein said two strips are outwardly convex and said third strip is flat.
 30. The vane of claims 1 or 3 wherein said flexible material is an elongated strip having elongated first and second side edges and first and second elongated folds, said second side edge being folded back along a third fold onto said material to form an elongated flap along said second side edge, and wherein said first fold is equaly spaced from said first side edge and said second fold and wherein said first side edge is positioned proximate said second fold and is secured to said strip proximate said second fold such that the portion of said strip between said second fold and said second side edge forms a divider of said tubular body dividing said body into two cells, said flap being secured to said strip internally of said tubular body.
 31. The vane of claim 30 wherein said divider is flat, and wherein the strip between said first side edge and said first fold is outwardly convex and between said folds is outwardly convex.
 32. The vane of claims 1 or 3 wherein said material is a nonwoven fabric.
 33. The vane of claims 1 or 3 wherein said material is a knit.
 34. The vane of claims 1 or 3 wherein said material is a laminate that includes at least one layer of fabric that is diagonally, dimensionally stable.
 35. The vane of claim 1 or 3 wherein said vane has a top edge and a bottom edge and wherein 10 grams or more of force are required to twist the bottom edge of the vertically extending vane that is suspended from its top edge when the vane is eighty-four inches in length and three and one-half inches wide.
 36. The vane of claim 2 or 3 where said fold is rounded.
 37. The vane of claim 2 or 3 wherein said strip of material is a laminate.
 38. The vane of claim 3 wherein said strip of material is a laminate of two layers and one of said layers is a diagonally dimensionally stable fabric.
 39. The vane of claim 1 or 2 wherein said material has diagonal dimensional memory.
 40. The vane of claims 1 or 2 wherein said vane is formed from a material which has diagonal, dimensional memory.
 41. The vane of claims 1 or 2 wherein said walls are of generally S-shaped configuration.
 42. The vane of claim 41 wherein said walls cooperate to define a pair of cells in the vane.
 43. The vane of claim 42 wherein said cells are crescent shaped. 